package cn.starboot.socket.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Objects;

public class SystemPropertyUtil {

	private static final Logger LOGGER = LoggerFactory.getLogger(SystemPropertyUtil.class);

	/**
	 * Returns {@code true} if and only if the system property with the specified {@code key}
	 * exists.
	 */
	public static boolean contains(String key) {
		return get(key) != null;
	}

	/**
	 * Returns the value of the Java system property with the specified
	 * {@code key}, while falling back to {@code null} if the property access fails.
	 *
	 * @return the property value or {@code null}
	 */
	public static String get(String key) {
		return get(key, null);
	}

	/**
	 * Returns the value of the Java system property with the specified
	 * {@code key}, while falling back to the specified default value if
	 * the property access fails.
	 *
	 * @return the property value.
	 *         {@code def} if there's no such property or if an access to the
	 *         specified property is not allowed.
	 */
	public static String get(final String key, String def) {
//		checkNonEmpty(key, "key");
		if (Objects.isNull(key))
			return null;

		String value = null;
		try {
			if (System.getSecurityManager() == null) {
				value = System.getProperty(key);
			} else {
				value = AccessController.doPrivileged(new PrivilegedAction<String>() {
					@Override
					public String run() {
						return System.getProperty(key);
					}
				});
			}
		} catch (SecurityException e) {
			LOGGER.warn("Unable to retrieve a system property '{}'; default values will be used.", key, e);
		}

		if (value == null) {
			return def;
		}

		return value;
	}

	/**
	 * Returns the value of the Java system property with the specified
	 * {@code key}, while falling back to the specified default value if
	 * the property access fails.
	 *
	 * @return the property value.
	 *         {@code def} if there's no such property or if an access to the
	 *         specified property is not allowed.
	 */
	public static boolean getBoolean(String key, boolean def) {
		String value = get(key);
		if (value == null) {
			return def;
		}

		value = value.trim().toLowerCase();
		if (value.isEmpty()) {
			return def;
		}

		if ("true".equals(value) || "yes".equals(value) || "1".equals(value)) {
			return true;
		}

		if ("false".equals(value) || "no".equals(value) || "0".equals(value)) {
			return false;
		}

		LOGGER.warn(
				"Unable to parse the boolean system property '{}':{} - using the default value: {}",
				key, value, def
		);

		return def;
	}

	/**
	 * Returns the value of the Java system property with the specified
	 * {@code key}, while falling back to the specified default value if
	 * the property access fails.
	 *
	 * @return the property value.
	 *         {@code def} if there's no such property or if an access to the
	 *         specified property is not allowed.
	 */
	public static int getInt(String key, int def) {
		String value = get(key);
		if (value == null) {
			return def;
		}

		value = value.trim();
		try {
			return Integer.parseInt(value);
		} catch (Exception e) {
			// Ignore
		}

		LOGGER.warn(
				"Unable to parse the integer system property '{}':{} - using the default value: {}",
				key, value, def
		);

		return def;
	}

	/**
	 * Returns the value of the Java system property with the specified
	 * {@code key}, while falling back to the specified default value if
	 * the property access fails.
	 *
	 * @return the property value.
	 *         {@code def} if there's no such property or if an access to the
	 *         specified property is not allowed.
	 */
	public static long getLong(String key, long def) {
		String value = get(key);
		if (value == null) {
			return def;
		}

		value = value.trim();
		try {
			return Long.parseLong(value);
		} catch (Exception e) {
			// Ignore
		}

		LOGGER.warn(
				"Unable to parse the long integer system property '{}':{} - using the default value: {}",
				key, value, def
		);

		return def;
	}

	private SystemPropertyUtil() {
		// Unused
	}
}
